Seal

ABSTRACT

A seal for a chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure is disclosed. The seal surrounds the opening. A workpiece is movable relative to the opening and defines with the seal a controlled gap of limited width as the workpiece moves relative to the opening in the work chamber. The controlled gap is operable to retard the differential flow of the fluid through the controlled gap, to create turbulence in the fluid in the controlled gap, and to build up a back pressure of the fluid in the work chamber so that the differential flow of the fluid through the controlled gap is substantially minimized and the fluid pressure within the work chamber remains substantially constant during the movement of the workpiece relative to the opening.

United States Patent] 1 Bengel et al.

[111 3,759,662 [451 Sept. 18,1973

211 Appl. No.1 88,029 Y 52 vs. Cl. 432/242, 34/242 [51] Int. Cl. F27b9/28, F26b 25/00 [58] Field of Search 263/50; 134/242; 13/17; 432/8, 59, 242

[ 56] I References Cited I y UNITED STATES PATENTS 3,667,626 6/1972 Torelli 34/242 3,349,578 10/1967 Greer et al 34/242 X 3,418,756 12/1968 Baughman et 34/242 X 2,640,860 6/1953 l-lerres 13/17 X 3,351 ,348 11/1967 4 Dupuis 34/242 X 28 From Plasma 30 Arc 60$. pp y 7' 0 Exhaust Gas Removal System 3,048,992 8/1962 Nakaguchi 34/242 X Primary Examiner-John J. Cambv Attorney-Robert J. Leek, Jr.

[571' 1 j ABSTRACT A seal for a chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure is disclosed. The seal surrounds the opening. A workpiece is movable relative' to the opening and defines with the seal a controlled gap of limited width as the workpiece moves relative to the opening in the work chamber. The controlled gap is operable to retard the differential flow of the. fluid through the controlled gap, to create turbulence in the fluid in the controlled gap, and to build up a back pressure of the fluid in the 'work chamber so that the differential flow of the fluid through. the controlled 7 gap is substantially minimized and the fluid pressure within the work chamber remains substantially constant during the movement of the workpiece relative to the opening.

11 Claims, 12 Drawing Figures From Plasma l6 Arc Gas pp y F ram lner/ Gas Supply PAIENTEDSEHBW 3.759.662

' sum 1 or 4 From Plasma Arc Gas pp y From Plasma Arc Gas 7'0 Exhaust Gas Removal System I.

ram Inert Gas Supply 64 45 72 as) 68 HI I I f/V// I llVVE/VTORS THOMAS G. BEA/GEL 40 8 THOMAS E NIGEL) 34 AI/amey SEAL OBJECTS OF THE INVENTION It is the general object of this invention to avoid and overcome the foregoing and other difficulties. of and objections to prior art practices by the provision of an improved seal for use between the entry portion of a chamber having a controlled fluid atmosphere therein and a workpiece which is to beintroducedinto and withdrawn from such chamber. This improved seal:

a. maintains a seal regardless of feedstock shape and is simple in construction; v

- b. is easy to assemble;

c. is composed of single components that can be replaced independently;

d. is resistant to abrasion;

e. has the ability to conform to nonparallel surfaces and retain sealing capabilities;

f. will operate at temperatures up to about 1,400 F;

g. can retain sealing capabilities while the work'on feedstock shifts laterally;

h. is applicable to large feedstock sizes;

i. is modular in construction;

j. is one in which the size of the module can be varied thus providing the necessary flexibility for a particular application; v

k. can be used on feedstock moving in a horizontal or vertical plane; and

l. is capable of being used as a fixed gap seal, a line seal, or as a multilevel line seal.

. BRIEF SUMMARYOF THE INVENTION The aforesaid'objects of this invention, and other objects which will become apparent as the description proceeds are achieved by providing an improved seal for a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differensubstantially minimized and the fluid pressure within the work chamberremains substantially constant during the movement of the workpiece relative to the opening.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS For a better understanding of this invention, reference should be had to the accompanying drawings, wherein like numerals of reference indicate similar parts through the several views and wherein:

FIG. I is a schematic vertical sectional view'of a plasma are cold mold work chamber showing the entry opening and the improved movable seal of this invention, the seal having a substantially rigid seal member defining the controlled gap with the workpiece;

FIG. 2 is an enlarged fragmentary view of the controlled gap, irregular surface of the workpiece, the rigid seal member, theseal base plate, and a portion of the slide plate;

FIG. 3 is a fragnentary view similar to the upper portions of FIG. 1 showing an alternative seal having a resilient seal member;

FIG. 4 is an enlarged fragmentary view of the controlled gap shown in FIG. 3;

FIG. 5 is a plan view of the resilient seal member shown in FIG. 3 showing the overlapping of the butt joints between the half sections of each laminate in the resilient seal member and also the overlapping of radial slits in the corners of the laminates making up the resilient seal member;

' FIG. 6 is a vertical sectional view taken along the line 6--6 of FIG. 5 in the direction of the arrows with the bending slits omitted for clarity;

FIG. 7 is a view similar .to FIG. I of another seal embodiment showing a plurality of resilient seal members and a flexible sheath surrounding the resilient seal members;

FIG. 8 is an enlarged fragmentary view of a portion of FIG. 7 showing the irregular surface on the workpiece, the resilient sheath and the resilient sealing members; 1

FIG. 9 isa plan view'of theresilient sheath and resilient sealing members taken along the line 99 of FIG. 7 in the direction of the arrows with the workpiece omitted for clarity;

FIG. 10 is an enlarged fragmentary view similar to the right-hand portion of FIG. 7 of an alternative seal showing a first resilient seal section, asecond resilient seal section, inert curtain gas inlets, and cooling fluid means connected to the spacer members and between such resilient seal sections;

FIG. 11 is a diagrammatic side elevational view of a typical continuous vacuum metallic (for example, aluminum coating) line utilizing the improved seals of this invention; and

FIG. 12 is a fragmentary view similar to a portion of FIG. 8 showing the alternative use of lugs and springs as a replacement for the resilient sealing members.

Although the principles of this invention are broadly applicable to an improved seal for a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure, this invention is particularly adapted for use in conjunction with a plasma are cold mold work chamber and hence it has been so illustrated and will be so described.

= DETAILED DESCRIPTION With specific reference to the form of this invention illustrated'in the drawings, and referring particularly to FIG. I, a plasma are cold mold apparatus is indicated generally by the reference numeral 10.

This apparatus 10 (FIG. 1) has a work chamber 12 (FIG. ll) provided with an entry aperture or opening I4 (FIG. I) defined by an entry aperture plate orring I6 (FIG. I) on the upper portions of the work chamber 12. In the conventional manner, the apparatus I0 is provided with apair of plasma-arc torches 18 (FIG. 1 an exhaust gas outlet 20 (FIG. 1), an inert gas inlet 22 (FIG. I), and at its bottom portions, as viewed in FIG. I, with a cold mold device 24. The work chamber 12 is adapted to hold a protective fluid such as, for example, argon, nitrogen, or the like, having a fluid pressure difierential with respect to atmospheric pressure, such as for example, plus about 3-5 oz/sq.in. above atmospheric pressure.

SEAL 26 A seal 26 (FIGS. 1,2) of the present invention surrounds the entry. aperture 14. This seal 26 has a seal base plate 28 (FIG. 1) secured by means of a gasket ring 30 (FIG. 1) and bolts and nuts, welding, or the like (not shown) to the flange portions of the entry aperture plate 16. The seal base plate 28 carries a plurality of low-friction type inserts or rollers 32 (FIG. 1) suitably formed of graphite or the like. A seal slide plate 34 (FIGS. 1,2) slides on the rollers 32 and is secured by means of spring biased hold-down pins 36 (FIG. 1) projecting downwardly from step clamps 38 (FIG. 1) in substantially hermetic sealing and sliding engagement with the rollers 32. A seal base plate 40 (FIGS. 1,2), secured by welding or the like to the seal slide plate 34 projects upwardly as shown in FIGS. 1,2 from the seal slide plate 34 and carries on its upper flange 35 a substantially rigid sealing member 42 (FIGS. 1,2), such sealing member 42 being secured to the flange 35 of the seal base plate 40, as by welding or the like. The upwardly extending flange 44 of the rigid sealing member 42 has a width W, and defines with a workpiece, such as a billet, plate or the like 46, a controlled gap CG (FIGS. 1,2) of limited width W (FIG. 2) as the workpiece moves relative to the entry opening 14 in the work chamber 12.

The controlled gap CG (FIGS. 1,2) is operable to retard the differential flow of the protective fluid through such controlled gap CG, to create turbulence in the fluid in the controlled gap CG (FIG. 2) as aided by the irregular surface S, (FIG. 2) of the workpiece 46, and to build up a back pressure P, (FIG. 1) of the protective fluid in the work chamber 12 so that the differential flow of the protective fluid through the controlled gap CG is substantially minimized and the fluid pressure within the work chamber 12 remains substantially constant at about +3 oz/sq.in. above atmospheric pressure during movement of the workpiece 46 in the direction of the arrows (FIGS. 1,2) through the entry aperture or opening 14.

It will be noted from a consideration of FIG. 1 that the seal base plate 40 carries a plurality of guide rollers 47 mounted by means of brackets 47a on the seal base plate 40. If for some reason, the workpiece 46 should shift laterally during its movement through the entry aperture 14, either to the right or left as viewed in FIG. 1, the contacted guide rollers 47 move the slide plate 34 on the graphite inserts or rollers 32 to maintain substantially constant the width W of the controlled gap CG.

It will be understood that for high temperature applications, the seal 26 may be formed of stainless steel or the like and for low temperature chemical applications resilient plastic, such as polypropylene, nylon, or the like may be used.

ALTERNATIVE EMBODIMENTS It will be understood by those skilled in the art that alternatively as shown in FIGS. 3-6, the seal 26 has a seal mounting plate 48 (FIGS. 3,4) secured as by bolts 64 and nuts 66, welding, or the like to the flange 35 of the seal base plate 40, and carries a resilient sealing member 50 (FIGS. 3-6) on its inner portions. This resilient sealing member 50, shown in detail in FIGS. and 6, is formed of a plurality of laminates 50a,50b,50c, and 5011 (FIG. 6), each laminate being formed as shown in FIG. 5, either integrally (not shown) or in half sections 540,541) (FIG. 5) which half sections 54a,54b butt together, as for example in the case of the first laminate 50a and the third laminate 500 on the solid lines 560 and 56b (FIG. 5). The second laminate 50b and fourth laminate 50d (FIG. 5) may also be formed in half sections 54a, 54b which half sections 54a,54b are butted together along dotted lines 560 and 56d (FIG. 5). Such solid lines 56a and 5612 are spaced from the dotted lines 560 and 56d by a suitable distance such as d to prevent leakage of the protective fluid through the joints or lines 56a through 56d of the half sections 54a,54b,etc. of the resilient sealing member 50. For the purpose of permitting bending of the resilient sealing member 50 adjacent the corners 60 (FIGS. 1,3) of the workpiece 46, the first and third laminations 50a,50c may be provided with a plurality of bending apertures or radial slits, slots, or the like 58a,58b,58c and 58d shown in the solid lines of FIG. 5 adjacent each comer 60a (FIG. 5) of the workpiece cavity 62 (FIG. 5) in the resilient sealing member 50. The second laminate 50b and the fourth laminate 50d are similarly provided with similar bending apertures 58a',58b,58c' 58d, and 58a, shown in the dotted lines of FIG. 5, which radial bending apertures or slits 58a-58e' are suitably spaced an angular distance, such as about 5-l0 from the adjacent bending apertures or radial slits 58a-58d in the first laminate 50a and third laminate 500.

The means utilized to mount the resilient sealing member 50 on'the seal mounting plate 48 may comprise a plurality of bolts 64 and nuts 66 (FIGS. 3,4) extending through mounting holes 68 (FIGS. 3-6) in the resilient sealing member 50 and the seal mounting plate 48.

FIGS. 7,8,9 show a plurality of resilient sealing members 50" having a plurality of sealing members 50, which members 50 are stacked at 76 and spaced from each other on hollow spacers 70 and secured by a plurality of bolts 64 and nuts 66 or the like, not shown for clarity in FIG. 7, to the flange 35 of the seal base plate 40 on the bottom of the stack 76 and to a top mounting plate or ring 72 (FIGS. 7,8) with a resilient shield 74 (FIGS. 7-9) surrounding the resilient seal members 50 and defining the controlled gap CG (FIG. 8) with the workpiece 46.

This resilient shield 74, shown particularly in FIG. 9,

has a pair of opposed substantially long shield members 74a and a pair of short shield members 74b (FIG. 9). The short shield members 74b, as shown in FIG. 9, are flared outwardly on their top and bottom portions 74b to permit alignment in the stack 76 (FIG. 7) of their top and bottom portions 74b with the mounting holes 68 in such top and bottom portions 74b, (FIG. 9), the top mounting plate 72 (FIG. 7), the resilient sealing members 50 (FIG. 9), the spacers 70 (FIG. 8), and the seal mounting plate 40 (FIG. 8).

FIG. 7 also shows a resilient baffle member 50a projecting below the resilient shield 74 which member 50a functions as a radiation shield for the seal 50.

Referring now to FIG. 10, the seal 26" has a first resilient seal section 10a and a second resilient seal section 10b. The stack 76" differs from the stack 76 shown in FIGS. 7-9 by the addition of a resilient rubber, plastic or the like seal 78 disposed at the top of a stack 76". Each of the resilient seal sections 10a has a plurality of, for example, three resilient sealing members 50 surrounded by a resilient shield 74. In addition,

the seal 26" is provided with an inert curtain gas inlet line 80 (feeding into the space 81 between sections la,10b) for obstructingthe differential flow of the protective fluid from the work chamber 12 through the controlled gap CG; cooling fluid inlet lines 82 which extend through the spacers 70 and into the cavity 83 defined by the resilient shield 74; and cooling fluid inlet lines 84 extending into the substantially hollow spacers 70. These cooling lines Blend 84 introduce cooling fluid, such as air or the like, into the resilient seal sections Illa and b to provide cooling therefor. It will be noted at the bottom of FIG. Ill that an additional inert curtain gas inlet line 80' may be provided through the seal base plate 40 adjacent the guide rollers 47 to similarly provide another inert curtain gas stream for obstructing the upward flow of the protective fluid from the work chamber 12 through the controlled gap CG.

In FIG. I I, the workpiece 46", suitably a steel sheet 0 II, horizontal and vertical seals 26 are shown. The

seals 26" may be any one of the above described types.

FIG.- 12 shows the resilient sealing members 50 as springs secured as by'welding or the like to lugs 98.

SUMMARY OF TI-IE ACHIEVEMENTS OF THE OBJECTS OF THE INVENTION It will be recognized by those skilled in the art that the objects of this invention have been achieved by providing improved seals 26' (FIGS. 1 and 2), 26 (FIGS.-

3-6), 26" (FIGS. '7-9), 26 (FIG. 10), and 26" (FIG. II) for a work chamber 12 having an entry aperture 14 therein and adapted to hold a protective fluid having a fluid pressure differential with respect to atmospheric pressure. The improved seals 26,26 ,26'26 and26 maintain a seal regardless of the shape of the workpiece 46 and are simple in construction; are easy to assemble; are composed of single components which can be replaced independently; are resistant to abrasiornhav an ability to conform to the non-parallel irregular surfaces Si of the workpiece 46 and still retain their sealing capabilities; will operate at the temperatures up to about 1,400 adjacent the bottom portions of such seals, and

at temperatures of about 500-600 F adjacent the-atmospheric portions of such seals; can retain their sealing capabilities while the workpiece 46 shifts laterally with respect to the entry aperture Id; are applicable to a wide range of large feedstock sizes; are modular in construction; are seals in which the size of the module can be varied thus providing the necessary flexibility for a particular application; can be used on a feedstock 46 movingin a horizontal or vertical direction; and

are capable of being used as a fixed gap seal, single line c. said seal having means which is adapted to provide a controlled gap of limited width and effective length with a workpiece movable relative to said opening in said work chamber; and

d. said means on said seal being operable to retard the differential flow of said fluid through said controlled gap when a workpiece moves relative to said opening in said work chamber, to create turbulence in said fluid in said controlled gap and to build up aback pressure of said fluid in said work chamber so that the differential flow of said fluid through said controlled gap is substantially minimized and the fluid pressure within said work chamber remains substantially constant during the movement of said workpiece relative to said open- 8;

e. said seal having a resilient seal means defining said controlled gap with said workpiece;

f. said seal means being laminated; and

g. said seal means having a first lamination provided with a first bending aperture adjacent one corner of said workpiece and a second lamination provided with a second bending aperture adjacent said one corner of said workpiece, said second bending aperture being offset from said first bending aper- -ture to prevent leakage of said differential fluid through said first bending aperture and said second bending aperture.

2. In combination:

a. a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure;

b. a seal surrounding saidopening;

c. said seal having means whichis adapted to provide a controlled gap 'of limited width and effective length with a workpiece movable relative to .said opening in said work chamber;

d. said means on said seal being operable to retard the differential flow of said fluid through said controlled gap when a workpiece moves relative to said opening in said work chamber, to create turbulence in said fluid in said controlled gap and to build up a back pressure of said fluid in said work chamber so that the differential flow of said fluid through said controlled gap is substantially minimized and the fluid pressure within said work chamber remains substantially constant'during the movement of said workpiece relative to said openmg;

c. said seal having a resilient seal means defining said controlled gap with said workpiece;

f. said seal having a second resilient seal means (FIG.

7) spaced from said resilient seal means; and

- g. said seal-having a resilient shield (FIG. 8) surrounding said resilient seal means and adapted to define said controlled gap with said workpiece.

3. In combination:

a. a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure;

b. a seal surrounding said opening; I

c. said seal having means which is adapted to provide a controlled gap of limited width and effective len with a workpiece movable relative to said opening in said work chamber;

d. said means on said seal being operable to retard the differential flow of said fluid through said controlled gap when a workpiece moves relative to said opening in said work chamber, to create turbulence in said fluid in said controlled gap and to build up a back pressure of said fluid in said work chamber so that the differential flow of said fluid through said controlled gap is substantially minimized and the fluid pressure within said work chamber remains substantially constant during the movement of said workpiece relative to said openand having a shield member below said resilient seal means to protect said seal from heat radiation from said work chamber.

4. The combination recited in claim 3 wherein said seal is movable laterally with respect to said opening by said workpiece thereby maintaining the width of said controlled gap substantially constant.

5. The combination recited in claim 3 wherein said seal has a substantially rigid seal means defining said ient seal section.

effective length and limited width of said controlled gap with said workpiece.

6. The combination recited in claim 3 wherein said seal has a resilient seal means defining said controlled gap with said workpiece. I

7. The combination recited in claim 6 wherein said seal means is laminated.

8. The combination recited in claim 6 wherein said seal has a second resilient seal means spaced from said resilient seal means.

9. The combination recited in claim 8 wherein said seal has a spacer means disposed between said resilient seal means and a second resilient seal means.

10.. The combination recited in claim 3 wherein said seal is fluid cooled. 4

11. The combination recited inclaim 3 wherein said seal has a first resilient seal section and a second resil- *sass s 

1. In combination: a. a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure; b. a seal surrounding said opening; c. said seal having means which is adapted to provide a controlled gap of limited width and effective length with a workpiece movable relative to said opening in said work chamber; and d. said means on said seal being operable to retard the differential flow of said fluid through said controlled gap when a workpiece moves relative to said opening in said work chamber, to create turbulence in said fluid in said controlled gap and to build up a back pressure of said fluid in said work chamber so that the differential flow of said fluid through said controlled gap is substantially minimized and the fluid pressure within said work chamber remains substantially constant during the movement of said workpiece relative to said opening; e. said seal having a resilient seal means defining said controlled gap with said workpiece; f. said seal means being laminated; and g. said seal means having a first lamination provided with a first bending aperture adjacent one corner of said workpiece and a second lamination provided with a second bending aperture adjacent said one corner of said workpiece, said second bending aperture being offset from said first bending aperture to prevent leakage of said differential fluid through said first bending aperture and sAid second bending aperture.
 2. In combination: a. a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure; b. a seal surrounding said opening; c. said seal having means which is adapted to provide a controlled gap of limited width and effective length with a workpiece movable relative to said opening in said work chamber; d. said means on said seal being operable to retard the differential flow of said fluid through said controlled gap when a workpiece moves relative to said opening in said work chamber, to create turbulence in said fluid in said controlled gap and to build up a back pressure of said fluid in said work chamber so that the differential flow of said fluid through said controlled gap is substantially minimized and the fluid pressure within said work chamber remains substantially constant during the movement of said workpiece relative to said opening; e. said seal having a resilient seal means defining said controlled gap with said workpiece; f. said seal having a second resilient seal means (FIG. 7) spaced from said resilient seal means; and g. said seal having a resilient shield (FIG. 8) surrounding said resilient seal means and adapted to define said controlled gap with said workpiece.
 3. In combination: a. a work chamber having an opening therein and adapted to hold a fluid having a fluid pressure differential with respect to atmospheric pressure; b. a seal surrounding said opening; c. said seal having means which is adapted to provide a controlled gap of limited width and effective length with a workpiece movable relative to said opening in said work chamber; d. said means on said seal being operable to retard the differential flow of said fluid through said controlled gap when a workpiece moves relative to said opening in said work chamber, to create turbulence in said fluid in said controlled gap and to build up a back pressure of said fluid in said work chamber so that the differential flow of said fluid through said controlled gap is substantially minimized and the fluid pressure within said work chamber remains substantially constant during the movement of said workpiece relative to said opening; e. and having a shield member below said resilient seal means to protect said seal from heat radiation from said work chamber.
 4. The combination recited in claim 3 wherein said seal is movable laterally with respect to said opening by said workpiece thereby maintaining the width of said controlled gap substantially constant.
 5. The combination recited in claim 3 wherein said seal has a substantially rigid seal means defining said effective length and limited width of said controlled gap with said workpiece.
 6. The combination recited in claim 3 wherein said seal has a resilient seal means defining said controlled gap with said workpiece.
 7. The combination recited in claim 6 wherein said seal means is laminated.
 8. The combination recited in claim 6 wherein said seal has a second resilient seal means spaced from said resilient seal means.
 9. The combination recited in claim 8 wherein said seal has a spacer means disposed between said resilient seal means and a second resilient seal means.
 10. The combination recited in claim 3 wherein said seal is fluid cooled.
 11. The combination recited in claim 3 wherein said seal has a first resilient seal section and a second resilient seal section. 